EMAX Bullet Series 20A ESC

Preflight:

Emax just recently released their latest line of ESC’s – the Bullet Series. I originally came across these ESC’s on Banggood as a pre-order item. However, opting for faster shipping, I decided to purchase them from Piroflip (they even had them available the same day and price as Banggood).

I’m finding out that many ESC’s are fairly equal lately in terms of size, price, and weight. The Bullet Series has everything you could want going for it:

  • Oneshot125
  • Oneshot42
  • Multishot
  • Dshot
  • Smallest 20A ESC (that I know of)
  • 30A Burst
  • 3.5g (without wires)
  • Heat sink (dual purpose)
  • 2S-4S

Packaging:

The Bullet Series ESC’s come packaged with the power wires (20awg) and signal/ground wires already soldered. It also comes along with three 50mm long 20awg motor wires that are not soldered to the ESC, but already stripped and pre-tinned. Most motor wires are long enough to reach the ESC and time is saved by not having to remove pre-soldered wires off of the ESC. The package also includes shrink tube to cover the ESC once the motor wires are soldered.

emax-bullet-20a-08
Packaging with yellow sticker denoting which Blheli_S version it is flashed with

Genuine Emax:

The packaging also comes with a sticker that has a scratch off area that reveals a code. If you visit the Emax website, there is an anti-counterfeit link near the top of the page. Enter in the code to verify the ESC is a genuine Emax product.

emax-anticounterfeit-02

emax-anticounterfeit-03

Heat sink:

This is the main reason I bought this ESC since my builds typically don’t allow for much air flow. However, I did notice that the heat sink is rather large – it covers all the MOSFET side electronics. The reason, according to Emax, is that it will help to protect the electrical components in the case of a crash. I can think of at least one instance when this would have been helpful where my son crashed his quad into a tree – one of the Littlebee ESC’s was destroyed due to a propeller strike.

emax-bullet-20a-09
The heat sink not only cools, it also protects

Size:

I thought the Spedix ES 20’s were small but the Emax ESC’s are even smaller (although not by much). I measured these 2 ESC’s with calipers along with the Littlebee Pro 20a’s and got the following measurements:

  • Littlebee: 24.6mm x 12.6mm (310mm²)
  • Spedix: 24.4mm x 10.7mm (261mm²)
  • Emax: 19.6mm x 11.9mm (233mm²)

The Spedix is 16% smaller than the Littlebee while the Emax is 25% smaller than the Littlebee.

emax-bullet-20a-littlebee-pro-20a-mosfet-side
MOSFET Side: Emax top, Littlebee bottom
emax-bullet-20a-littlebee-pro-20a-mcu-driver-side
MCU/driver Side: Emax top, Littlebee bottom
emax-bullet-20a-spedix-es-20-mosfet-side
MOSFET Side: Emax top, Spedix bottom
emax-bullet-20a-spedix-es-20-mcu-driver-side
MCU/driver Side: Emax top, Spedix bottom

The project:

The project I’ll be using these on is the C3 Project which is a completely sealed, weatherproof frame. The frame will be like the C2 project except the body tube will be aluminum tubing (0.9mm wall thickness). This will allow the Bullet ESC’s to be mounted inside with their heat sinks in contact with the aluminum body so they dissipate heat in the absence of air flow.

Flight Test:

Unfortunately, I don’t have any video (worthy of posting) of the first few flights with these ESC’s but I will say that they definitely worked as intended for the C3 project and they are extremely smooth. Truthfully though, ever since blheli_s came out, I have not been able to notice any difference between different manufacturers. These are the only ESC’s that I have run with dshot so far. In the little bit of flying I was able to do, I haven’t been able to tell the difference with dshot either. However, even if I can’t tell the difference, I know the FC is getting a cleaner signal which helps everything in terms of accuracy and efficiency.

I Killed Them:

I outline the whole story on the C3 Project page…

2017_0217_20545700

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